The Mass Spectrometry Center at Virginia Commonwealth University currently consists of a Hewlett Packard 5988A quadrapole Mass Spectrometer (MS) that has been supported by the NIDA Center on Drug Abuse Research for the past eight years. We are requesting funds for the purchase of a MicroMass Quattro II MS in order to replace this instrument. The need for this replacement is two-fold: the Hewlett Packard 5988A has become outdated and it has limited capabilities. This proposal requests a multi-user instrument that will meet a wide range of MS needs within the university. Neuroscientists represent a major user group who are concentrating on drug abuse research. The primary thrust of their research has been the identification and quantitation of drugs in biological fluids where sensitivity is a major concern. Conversely, we have other researchers who are interested in the structural elucidation of carbohydrates, peptides and proteins where the availability of the state-of-the-art soft ionization capabilities is crucial. We have a third group of investigators who use direct probe for the structural verification of newly synthesized compounds. In order to accommodate the research needs of this wide range of scientists, we have chosen a Micromass Quattro II Triple Stage Quadropole Mass Spectrometer and the MassLynx-NT Mass Spectrometer Workstation. The Quattro II fulfills our needs because it has a multiple inlet adapter that accommodates direct probe, gas chromatography (GC) and liquid chromatography (LC) in contrast to almost to most instruments on the market that allow for either GC or LC, but not both. The Atmospheric Pressure Ionization LC-MS interface accommodates electrospray, nanospray, and atmospheric pressure chemical ionization that are particularly important for the structural elucidation of large molecules. Electron Ionization (EI) and Chemical Ionization (CI) capabilities are essential for full range of analyses by GC. The Direct Insertion Probe eliminates the need for development of either GC or LC methods for structural analysis of pure volatile samples. The HP 6890 GC will allow us to use many of the standard methods that have already been developed for quantitation of drugs biological fluids. The NIST library, BioLynx software, and the MaxEnt will provide us with reference spectra and allow us to sequence and determine molecular weights of proteins. We believe this requested instrumentation will allow these highly productive researchers to enhance their existing research programs as well as accommodate their needs for several years in the future.